When Barack Obama became President of the United States in 2009, it felt like a watershed moment for the country.

After a history of slavery, civil rights abuses and race riots, Obama’s inauguration was meant to see the U.S. transformed into a nation of integration, establishing it as the land of equal opportunity and the free that it had always positioned itself as being.

And yet President Obama’s departure has seen civil unrest grow, talk of walls being built and children separated from parents in a crackdown on illegal immigrants.

Is it any wonder, then, that Colin Kaepernick the former San Francisco 49ers quarter-back, refused to stand for the national anthem in 2016, prompting a national debate about freedom of speech, civil rights and the state of the nation and putting himself at the centre of a national storm of controversy?

“I am not going to stand up to show pride in a flag for a country that oppresses black people and people of color,” Kaepernick told NFL Media. “To me, this is bigger than football and it would be selfish on my part to look the other way. There are bodies in the street and people getting paid leave and getting away with murder.”

Kaepernick has been without a team since his stance polarised national opinion and he subsequently decided to opt out of his contract.

The debate has returned to public consciousness this week when Nike, who have had their fair share of ethical controversies themselves, decided that Kaepernick would front their latest advertising campaign.

It sends out a loud message about their views on the role of sportspeople who can use their status to highlight issues that might otherwise not get the exposure they warrant.

“Believe in something. Even if it means sacrificing everything,” the advert says as billboards appeared across America featuring Kaepernick and the campaign.

Nike clearly see this as a commercial opportunity, following on from the equality campaign they launched earlier this year, with the focus shifting to millennials.

Strong feels abound on both sides of the debate, with thousands abandoning the brand and taking to social media using hashtags such as #DumpNike, #JustBurnIt and #NikeBoycott featuring apparel being burned or torn.

President Donald Trump, who has often criticised Kaepernick, said that the Nike campaign sent a “terrible message” which some may see as validation for the undertaking in the first place.

Serena Williams admitted her pride and added that the campaign “was a really powerful statement to a lot of other companies.”

Kaepernick’s views and subsequent Nike campaign have been praised by the NFL, clearly appreciating that highlighting social issues and injustice is something sports stars are right to embrace.

“The National Football League believes in dialogue, understanding and unity. We embrace the role and responsibility of everyone involved with this game to promote meaningful, positive change in our communities. The social justice issues that Colin and other professional athletes have raised deserve our attention and action.”

Kaepernick is not the first athlete to make a stand for social issues, of course.

The last 100 years have seen plenty of incidents where black American athletes have been at the centre of political storms.

At the 1936 Olympic Games in Berlin, staged amid a backdrop of Nazi propaganda to promote the Aryan ideal, Jesse Owens won four gold medals, prompting the alleged ire of Fuhrer Adolf Hitler.

Curiously, American coaches had dropped Sam Stoller and Marty Glickman ahead of the fourth of Owens’ triumphs, the 4x100m relay, despite their times being faster than others on the team. Both were Jewish and the reasons for them being dropped remain a matter of debate.

At the peak of his fame and sporting success, Muhammad Ali was stripped of his titles for refusing to go to war in Vietnam.

This was a time where blacks and whites in America had to sit in separate areas on a bus and police brutality was rife.

“I ain’t got no quarrel with them Vietcong,” he told reporters in 1966. “No Vietcong ever called me n*****. Why should they ask me to put on a uniform and go 10,000 miles from home and drop bombs and bullets on brown people in Vietnam while so-called Negro people in Louisville are treated like dogs and denied simple human rights? I have been warned that to take such a stand would cost me millions of dollars. But I have said it once and I will say it again. The real enemy of my people is here. I will not disgrace my religion, my people or myself by becoming a tool to enslave those who are fighting for their own justice, freedom and equality.”

It was five years before Ali successfully appealed his arrest to the U.S. Supreme Court, by which many of his peak years had passed, although he did go on to retain the heavyweight crown.

At the 1968 Olympic Games in Mexico City, victorious sprinters Tommie Smith and John Carlos gave the black power salute on the podium as the national anthem played in yet another display of frustration at civil rights abuses.

Both were suspended from the U.S. team, ejected from the Olympic Village and vilified back home, where they struggled for work and received death threats.

In 1996, the N.B.A. suspended Mahmoud Abdul-Rauf, who had stopped standing for the national anthem during the 1995-96 season.

He too received death threats and his home was burned to the ground. His team, the Denver Nuggets, transferred him to the Sacramento Kings and his career soon petered out.

The New York Times put it at the time that “trying to force participation in a patriotic exercise undermines democratic values.” It was scant consolation for Abdul-Rauf.

Kaepernick’s actions show that there is still much work to be done.

Some athletes focus solely on their sport, the opposition and how to win. That’s their right.

As the New York Times wrote of Ali: “Possessing a killer jump shot or the ability to stop on a dime was no longer enough. What were you doing for the liberation of your people? What were you doing to help your country live up to the covenant of its founding principles?"

Kaepernick has chosen a similar path and for that he should be applauded.